I've been looking to find an air filter for my nc24 for an age and it has turned out to be a non starter. No one seems to make a filter for it anymore and mine was black with filth.

Enough is enough. Time to make my own.

I've been struggling with a bit of a dead spot at or just after 5000rpm so I'm hoping this along with a carb clean and rejet will help.

So for this project I shall use the existing filter as the housing, I ordered some 2stage foam from ram air and some stainless mesh and got some foam filter oil.

The process goes like this
1. Remove all paper section from the old filter I used a Stanley knife then cleaned the whole plastic chassis with some spirit to remove fuel and oil residue.
2. Cut some stainless steel mesh and fold to create a basket that fits tightly In to the opening from where the paper element used to be. I created a lip arround the top of the basket so when it drops into the chassis it won't pull through.
3. I proceeded to cut the foam filter element to the size of the chassis hole plus 2mm.
4. Then insert the foam element into the basket that's already in the filter chassis. This should fit snug against the plastic edge of the chassis.
5. Then run a bead of black silicone gasket between the top edge of the foam and the plastic chassis. Do this on both sides of the element to ensure there is a good seal and that air can only pass through the new foam element. Leave to dry for 24hrs
6. Oil the foam element ensuring you use just the right amount of oil, don't drown it.
7. Install it and start her up and go for a ride.

While I did this I went to see Rick Oliver and got some gaskets and new jets for the carbs, I went with 117.5 front 120 rear. I have a scorpion can on so suspected this should be a good setup with the flow of the new filter combo. I opened and cleaned the carbs and dirty they were too installed the new jets. Bench synced the butterflies and put it all back together onto new rubbers from eBay. The eBay rubbers are not good out of the pack they need some edge tidying due to poor cleanup after casting.

After all of this I put it back together and went for a ride. Well I must say this was successfull. That dead spot was no more.. Good riddance to it too. Bikes now running great again not bad for a 1987 machine.

Not a single reply, not even a sarky one...

not so many nc24 people about

i forgot it may have been Rick (not O) that did a guide on modifying the nc30 air filter to accept a k/n filter.. its not hard to carry it over to the nc24 filte.r

That sounds interesting any idea which k&n panel was used. Neo do you know where I can find that guide?

I've noticed that my rpm is dropping a little slowly between 3k and 1k and my tickover is slightly irratic? I think it might be a slight vacuum leak between the carbs and the adjoining tray would this make any sense?

I did rejet the carbs after cleaning but I didnt change the air screw setting.Would this help the irratic tickover. Its struggling to idle when cold and ticking over high when it warms up.

if it was fine beofre you messed then most likely an air-leak.. fuel vaccum tap pipe can leak air too..

old rubbers on these bikes a change is really a must when you do the carbs, they are not that expensive and will be goofd for another 20 years and save oodles of trouble.

worth noting the air screws and backing them in and resetting them to stock, somebody in the past could have messed with them to "fix" another symptom and cleaning the cabrs has sorted it out..

since they were off they might need a balance too, that could also throw your idlign out if they are way off.

did you check / adjust valve clearnaces while your in there?

urbanarcher wrote:That sounds interesting any idea which k&n panel was used. Neo do you know where I can find that guide?

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